Valve mechanism for rock drills



@at L 1935. w. A. SMITH, SR

VALVE MECHANISMFOR RQCK DRILLS Filed om. 4, 1934 m3. mm .wm u wmu Er we fl), Rm z 0 ww` r w v` IN f .HM TN /mv www. H

Kramm Fla/*S Patented Oct. 1, 1935 UNITED STATES PATENT GFFICE William A. Smith, Sr.,

Athens, Pa., assignor to Ingersoll-Rand Company, Jersey City, N. J., a corporation of New Jersey Application October 4, 1934, Serial No. 746,776

2 Claims.

This invention relates to rock drills, and more particularly to a valve mechanism for distributing pressure fluid to rock drills of the hammer type.

One object of the invention is to effect the distribution of pressure fluid in accordance with the requirements of the opposite end portions of the piston chamber.

Another object is to assure an immediate and abundant supply of pressure uid to the ends of the piston chamber at the instant communication is aiiorded between `the piston chamber and the source of pressure iiuid supply, and still another object is to enable the character of the blow of the hammer piston to be varied in accordance with variations in the nature of the rock being drilled.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawing illustrating the invention andA in which similar reference numerals refer to similar parts,

Figure l is a longitudinal elevation, in section, of a rock drill constructed in accordance with the practice oi the invention and illustrating the valves and the piston in one of their limiting positions, and

Figure 2 is a similar view showing the valves and the piston in another extreme position.

Referring more particularly to the drawing, 20 designates, in general, a rock drill comprising a cylinder 2l and front and back heads 22 and 23, respectively. Withinthe cylinder 2| is a piston chamber 24 containing a reciprocatory hammer piston 25 of which a front iiuted stem 26 extends into and slidably interlocks with chuck mechanism 21 disposed rotatably Within the cylinder and the front head.

Intermediate the ends of the piston chamber 24 is a free exhaust port 28 which is controlled by the piston, and a closure is provided for the rear end of the piston chamber by a plate 23. The plate 29 serves as a seat for a ratchet ring 36 and the head 3l of a rifle .bar 32 which extends through the plate 29 and is in splined engagement with the piston 25. The head 3| carries the usual spring-pressed pawls 33 for engagement with the ratchet ring to eiect a step-by-step rotary movement ci the chuck mechanism 2 and thus of a working implement 34 extending into the chuck mechanism. l

On the side of the cylinder 2| is a valve chest 35 which may be secured to the cylinder in any suitable and well known manner. vThe Valve chest 35 is recessed to provide a supply chamber 36 for pressure fluid. The supply chamber extends longitudinally of the cylinder 2i and is preferably of appro-Ximately the same length as the piston chamber 24. In the intermediate portion of the valve chest is a throttle valve 37 whereby the admission of pressure fluid into the supply chamber 36 may be controlled. The throttle valve 3l has a central chamber 38 which may be in constant communication with a source of pressure uid supply, and in the wall of the throttle valve is a port 39 to register with a port 45 in the valve chest and opening into the supply chamber 36.

The admission of pressure fluid to the front and rear ends of the piston chamber 24 is effected directly, thereto from the adjacent ends of the supply chamber 36 through inlet passages 4I and 42, respectively, The entrance ends of the inlet passages are defined by ribs 43 which may be of annular shape and extend into the supply passage 36.

Each inlet valve is controlled by a separate valve disposed coaxially with the ribs 4:3 of which the free ends constitute seating surfaces 44. The valves employed for this purpose, and designated 45 and 46, are in the form of sleeves arranged in valve chambers 4l and 48 in the iront `and rear ends, respectively, of the valve chest.

The valves are preferably identical in all essential respects. Each valve constitutes a skirt portion 43 which extends through the supply chamber 36 and the free end of which is adapted to seat against the seating surfaces 44 to control the adjacent inlet passage. Intermediate the end of the valve is an external pressure area 50 which `is constantly exposed to the pressure fluid in the supply chamber 35 for opening the valve.

On the outer end of the valve is an external flange 5| which lies in an enlarged portion 52 of the valve chamber and the outermost end of the flange constitutes an actuating area 53 against which pressure uid is intermittently introduced to shift the valves against the seats 44. Preferably the pressure vfluid employed for the latter purpose is introduced into the enlarged portion 52 by crossed tripper passages 54 and 55 of which the former leads from the enlarged portion 52 of the valve chamber 48 to a point in the piston chamber forwardly of the exhaust port 28, and the passage 55 leads from the Valve chamber 41 to the piston chamber 24 at a point rearwardly of the exhaust port 28.

Pressure huid flows constantly into the tripper passages through leak passages 56 connected with the supply chamber v36. Thus, as the piston 55 reciprocates the tripper passages are alternately blanked oil by the piston and placed in communication thereby with the free exhaust port. For example, when the piston occupies the position illustrated in Figure 1 it covers the tripper passage 55 and pressure fluid flowing into the tripper passage through the leak passage 5B then acts against the actuating area 53 of the valve 45 to shift the valve against its seating surface 44. In this position of the piston the tripper passage 54 is in communication with the exhaust port 23 and the pressure fluid acting against the Y pressure area 55 ofV the valve 46 will then raise the valve to admit pressure fluid into the rear end of the piston chamber 24.

Means are provided to enable the rate of flow of the pressure fluid entering the enlarged portions 52 of the valve chambers to be selectively controlled for causing the valves to be actuated to their closed positions either early or late in the stroke of the piston and thus to effect a desirable variation in the character of its blow.

To this endV continuations of the tripper passages 54 and 55 are formed in plugs 51 extending through the valves and carrying on their outer `ends flanges 58 which seat upon the valve chest to form` closures for the valve chambers 41 and 48.

The continuations of the tripper passages are shown as being in the form of notches or recesses 55 and 5l) in bosses 6I on the inner surfaces of the anges 58 and extending into the valve chambers 41 and 48. The recesses 59 and 65 are preferably disposed diametrically opposite each other in the bosses 6l and are of different capacity so that when the smaller recess, namely, Vthat designated 59, is in registry with a tripper passage the flow of pressure fluid into the enlarged portion 52 of the valve chamber will be somewhat restricted. The plugs 51 are secured to the valve chest 35 by bolts B2, and the top or outer surface of the plugs 51 may be Vprovided with suitable indicia (not shown) intended to indicate the positions of the recesses 59 and 5l) with respect to the tripper passages.

The operation of the device is as follows: With the piston in the position indicated in Figure 1 ofthe drawing, pressure fluid flowing into the trip-per passage 55 through the associated leak passage 55 passes through the recess 60 into the enlarged portion 52 of the Valve chamber 41. Such pressure fluid acting against the actuating area 53 presses the valve 45 against the adjacent seating surface 44. With the piston in this position the tripper passage 54 is in communication with the atmosphere through the front end of the piston chamber and the free exhaust port 28. The pressure fluid acting against the pressure area 58 of the valve 46 will then raise said valve and, together with that acting'against the inner end of the valve, will hold it open to admit pressure iluid directly from the supply chamber through the inlet passage 42 into the rear end of the piston chamber for driving the piston forwardly against the working implement 34.

As the piston proceeds forwardly it rst covers the free exhaust port 2,8, thence the tripper passage 54 and the pressure fluid leaking into the tripper passage will act against the actuating area 53 of the valve V46 and shift said valve to its seat 44, thus cutting off further admission of pressure fluid to the rear end of the piston chamber. The piston is thereafter actuated forwardly by the expansive force of the pressure Vfluid in the rear end of the piston chamber and when it uncovers the exhaust port 28 the actuating pressure rearwardly of the piston, as well as that acting against the actuating area 53 of the Valve 45, is exhausted to the atmosphere. The pressure fluid acting against the pressure area 50 of the valve 45 will then raise said valveto yadmit pressure fluid through the inlet passage 4| into the front end of the piston chamber for returning the piston. l l0 `Shortly after the piston covers the free exhaust port 28 it again covers the tripper passage 55 and pressure fluid leaking into the saidtripper passage then acts against the Vactuating area 53` of the valve 45 and moves said valve to its seat l5 44. The piston will then be carried rearwardly by the expansive force of the pressure fluid in the front end of the piston chamber until the exhaust port 28 is uncovered, whereupon the Y may then flow unretarded into lthe enlarged por- Y Y tions 52 of the valve chambers and the Valves 30 will, in consequence, be moved to their closed positions comparatively early in the'strokes of the piston. A reduced amount of pressure fluid is thereby admitted into the ends of the piston chamber.- Y 35 Should the character of the Work require a.

heavy blow, such as is delivered by causing the piston V25 to complete its full nominal stroke, the

' plugs 51 are shifted to place the recesses 59 in registry with the tripper passages. The re 40 cesses 59 being of smaller capacity than the tripper passages will serve to restrict the admission of pressure fluid into the enlarged portions 52 of the valve chambers. A slightly longerperiod of time is thus required to admit a full charge of pressure fluid into the enlarged portions of the valve chambers. The closing of the valves will thereby be slightly delayed and the periods for charging the ends of the piston chamber 50 will, as a result, be slightly prolonged.

I claim: Y

1. In a fluid actuated rock drill, the combination of a cylinder having a piston chamber and a piston therein, a valve chest having a supply 55 chamber extending longitudinally of the piston chamber, inlet passages opening directly from the ends of the supply chamber into the adjacent ends of the piston chamber, valve seats in the supply chamber encircling the inlet passages,'60

a pair of valve chambers in the valve chest, valves in the form of sleeves in the valve chambers cooperating withl the seats for controlling the admission of pressure fluid into the inlet passages, pressure areas on Vthe valves constituting portions of a bounding surface of the supply chamber and being constantly exposed to pressure lluid in the supply chamber for throwing the valves in one direction, actuatingk areas on the valves, passages controlled by the piston for 70 supplying pressure fluid to the actuating areas to throw the valves in the opposite direction, and closures for the valve chambers and being adjustable to different positions to vary the rate of flow of pressure fluid to the actuating surfaces.

2. In a fluid actuated rock drill, the combination of a cylinder having a piston chamber and a piston therein, a valve chest having a supply chamber extending along the length of the piston chamber, inlet passages affording direct communication between the ends of the supply charnber and the piston chamber, a pair of valve chambers in the valve chest having portions extending through the supply chamber to control the admission of pressure fluid into the inlet passages, each valve having a pressure area constantly subjected to pressure uid in the supply chamber for throwing the valves in one direction, actuating areas on the valves intermittently subjected to pressure uid for throwing the valves in the opposite direction, passages for supplying pressure fluid to the actuating area and being controlled by the piston, adjustable plugs forming closures for the valve chambers, and a plurality of recesses of different capacity in the plugs adapted to form continuations of the last said passages and being of different capacity whereby upon shifting the plugs to bring one or the other of the recesses into registry with the said passages the flow of pressure iiuid to the actuating areas may be varied.

WILLIAM A. SMITH, SR. 

